Electrically powered wheelchairs commonly have a chassis arrangement or a frame to which the seating system is mounted. The chassis arrangement may comprise a main chassis member that may house inter alia the battery unit which powers the electric motor of the wheelchair, pivot arms pivotally coupled to the main chassis member, to which pivot arms the wheels are mounted, and energy accumulation members, such as springs, which co-operate with the pivot arms for controlling the suspension of the wheelchair.
In existing electrically powered wheelchairs the main chassis member, or chassis box, is typically made of a number of sheet metal parts that are riveted or welded together. The sheet metal is typically very thin, generally 2-4 mm, in order to keep the weight of the main chassis member as low as possible.
To be able to obtain adequate road handling of a wheelchair comprising a main chassis member of the aforementioned type, the springs must be relatively stiff. The weakness of the main chassis member may thereby be compensated for. As a result, the comfort experienced by the user will be relatively low, because the stiff springs provide poor damping. In addition to the relatively poor comfort experience, there is a risk that the main chassis member may be damaged due to its design.